Do contested primaries help or hurt candidates for governor in Massachusetts?

Republicans have seen success limiting primary fights

Governor Deval Patrick has said that he will not run for a third term, meaning Massachusetts will have a wide-open race for Governor in 2014. Lieutenant Governor Tim Murray and Treasurer Steve Grossman have indicated they are thinking about running for the Democratic nomination, and there is speculation that former Republican gubernatorial nominee Charlie Baker may throw his hat into the ring for a second time. History shows that there will be more candidates putting their names in and out of contention before the final decision is made by the voters on November 4, 2014.

How does the number of candidates in a party's primary affect its nominee's performance in the general election? Massachusetts Democratic Party leader John Walsh is on the record as saying that he likes contested primaries because the party benefits from the competition. Others say that a contentious primary weakens the eventual nominee and reduces the chances of a general election win. Which of these notions is borne out by the facts? I try to shed some light on the matter by examining the performance of Democratic and Republican nominees for Massachusetts Governor since 1960.